hive窗口函数

lead(expr [, offset] [, default]) OVER([partition_by_clause] order_by_clause)

This function returns the value of an expression using column values from a following row. You specify an integer offset, which designates a row position some number of rows after to the current row. Any column references in the expression argument refer to column values from that later row.

替换

lag(expr [, offset] [, default]) OVER ([partition_by_clause] order_by_clause)

This function returns the value of an expression using column values from a preceding row. You specify an integer offset, which designates a row position some number of rows previous to the current row. Any column references in the expression argument refer to column values from that prior row.

也就是说 lead就是下一个窗口，lag就是上一个窗口
比如说：

select order_original_id,
stage,
user_due_at_datetime,
lead(user_due_at_datetime,1)over(partition BY order_original_id
                                 ORDER BY stage) AS NEXT,
lag(user_due_at_datetime,1)over(partition BY order_original_id
                                ORDER BY stage) AS BEFORE
FROM access_views.o_loanpro_v_t_repayment_schedule
WHERE loantype IN (3,20)
  AND stage IN (2,3,4)
  AND is_deprecated=0
ORDER BY order_original_id,
         stage